This study is the first multi-site evaluation of overdose training and naloxone distribution programs in the United States. It is also the first study to employ a psychometrically valid instrument to measure improvements in overdose recognition and naloxone administration knowledge. We found that people trained in overdose recognition and naloxone administration were comparable to medical experts in identifying situations in which an opioid overdose was occurring and when naloxone should be administered. Training programs improved recognition and response to opioid overdoses significantly, so that fewer opioid overdoses would be missed and fewer overdoses would be responded to inappropriately by trained participants.
Our findings suggest that non-opioid overdose knowledge is low, even among people who have been trained to recognize and respond to overdose situations. A review of training curricula at each site (see appendix mentioned previously) found that most of the training programs (four of six) do not address explicitly identification and responding to non-opioid overdoses, so the low non-opioid overdose knowledge scores in this study may be expected. Several recent studies have highlighted the role that cocaine plays in opioid overdose deaths [28
]. Overdoses with cocaine and heroin in combination, cocaine-only and cocaine, heroin and alcohol combinations are often experienced by drug users, yet their epidemiology is not well understood [29
]. Areas that have historically reported high abuse of cocaine and other stimulants such as the US eastern seaboard [32
], California [33
] and Canada [34
] may find muted effects of naloxone training programs on the prevalence of fatal drug overdose in their community. Curricula to recognize and respond to non-opioid overdose, especially cocaine intoxication, should be incorporated into naloxone trainings. For example, curricula could include explicitly addressing and practicing recognition of signs of cocaine/stimulant overdoses and a clear directive to call 911 in such circumstances.
The association between more recently witnessing an overdose and having been trained in overdose recognition and response may indicate that the people being trained by the programs are those exposed to settings in which the risk of overdose is high. In other words, the programs appear to be reaching their target population. Given relatively high knowledge scores among untrained participants, the association is less likely due to inability to recognize an overdose when it takes place. Among those who had recently witnessed an overdose, the greater median number of overdoses responded to by trained participants may not be due to success of training but rather to a reluctance of untrained participants to do anything that could potentially be harmful to the victim. Further evaluation studies pairing witnessed overdose and their specific response might elucidate this point.
It is important to note the relatively high opioid overdose symptom knowledge amongst untrained participants. While this may reveal a diffusion of knowledge from trained to untrained members in the community, it may also reflect the drug user community’s awareness of, concern about and organic efforts to educate others about overdose risk. Programs for overdose recognition and response often arise directly from or are built upon such cumulative foundations, influencing program mobilization and thus their efficacy. Further, diffusion of public health messages from those trained to those untrained increases program effectiveness and overdose risk minimization within the community.
Finally, this study found that people who have been trained in overdose–response techniques and who feel confident in their ability to recognize an opioid overdose may effectively prevent overdose mortality. Self-efficacy, or one’s perceived ability to engage in a specific behavior, is a prominent predictor of behavior change and action [37
]. The finding that perceived competency (i.e. self-efficacy) in recognizing opioid overdose was associated independently with greater knowledge of overdose recognition suggests that mechanisms to improve confidence in one’s abilities such as attending trainings and practicing newly acquired skills exert an influence on knowledge, a key mediator of behavior change. Moreover, self-efficacy to recognize both opioid and non-opioid overdoses were associated independently with ever responding to overdose, suggesting links between self-efficacy and behavior. For drug users, there may be a sense of empowerment and other important psychosocial benefits gained through receipt of overdose recognition and naloxone training. Future studies should further explore these potential benefits.
Cost-effectiveness of health interventions such as diagnostic screening is a function of the prevalence of the problem being alleviated, the frequency and cost of a false positive, and the frequency and cost of a false negative [40
]. In the case of naloxone training programs, the prevalence of opioid overdose is high among drug users but may differ by location depending on, among other things, accessibility to drugs other than opioids. This study demonstrated that the frequency of a false positive (i.e. ‘wasted resources’) and the frequency of a false negative (i.e. ‘missed opportunity’)were minimized with training. The cost of a false positive could range from the cost of the naloxone dose ($1.75–3.10 per 1 mg dose wholesale; Safetyworks: http://www.1800safety2.com
) to death, if the case was a non-opioid overdose. The cost of a false negative could range from nothing to death. Mitigating the influence of these costs is the capacity to train drug users and people who spend time around drug users in overdose recognition and response. This study provides key evidence, without having to conduct a large, costly, multi-site study or a complex cost–effectiveness analysis, that naloxone training programs are effective and probably cost–effective.
This study has several important limitations. Sample size was small, and power was insufficient to test for site-specific differences. For the main knowledge outcomes, however, the large effect sizes (Cohen’s d = 0.97 for overdose knowledge, d = 1.1 for naloxone indication knowledge) were detected with confidence using this sample size. Nevertheless, a larger scale evaluation could examine site and program-specific effects more thoroughly, provide adequate power for multivariable regressions to test hypotheses generated by our exploratory models and return results with greater external validity than our small study provides. This study is observational in nature and thus is open to the limitations of such designs including self-report and reporting bias. Moreover, the non-random sampling strategy employed to recruit subjects at each site may have introduced bias. We made every effort to convey the importance of recruiting a random sample of participants trained and untrained at each site. In all cases, the programs’ time and staff constraints would have made orchestration of a non-random selection-biased recruitment effort unlikely. Another limitation pertains to the lack of specificity in the data obtained, namely that the overdoses witnessed were not necessarily the same overdoses that were responded to by participants (i.e. unpaired overdose situations). Instead, interpretation is restricted to associations between participants’ reports of witnessing and responding to overdoses in general. Finally, due to time and space constraints at the sites, the evaluation instrument collected limited demographic variables. Thus, residual confounding may have influenced the findings.
In conclusion, this study reports initial evidence of the effectiveness of overdose training and naloxone distribution programs in opioid overdose recognition and response. People trained through these programs identify opioid overdoses and indications for naloxone as well as medical experts and consistently scored higher in knowledge of overdose and naloxone indication scenarios than their untrained counterparts. Efforts to develop and incorporate curricula for recognizing and responding to non-opioid overdoses, especially cocaine intoxication, are needed. Expansion of overdose training and naloxone distribution programs for drug-using populations is warranted.